Peter Ben Embarek, the head of the WHO mission, said more work was needed to identify the source of the virus. Experts believe the virus is likely to have originated in animals before spreading to humans, but they are not sure how.
The members of the mission consisted of 17 Chinese experts and an equal number of counterparts from other nations. The team arrived in Wuhan on Jan. 14 and after two weeks of quarantine, visited key sites, including the Huanan seafood market, the location of the first known cluster of infections, as well as the Wuhan Institute of Virology, which has been involved in COVID-19 research.